<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div class="all">
    <form method="post" action="/upload" enctype="multipart/form-data">
        用户名: <input name="username" type="text"/><br/>
        密码: <input name="password" type="password"/><br/>
        头像:<input type="file" name="file"/><br/>
        <button type="submit">提交</button>
    </form>
</div>
</body>
</html>